An engaged session exceeds the configured engagement-time threshold, has a key event, or has at least two page or screen views. The default time threshold is 10 seconds and can be adjusted for a web data stream.
A session is a bounce when none of these conditions is met. GA4 bounce rate therefore equals 100% minus engagement rate. The presence of a scroll or video event alone does not necessarily satisfy the engaged-session criteria.
Interpret bounce rate alongside the page purpose, traffic source, and measurement settings. A visitor who quickly finds information and a visitor who fails to submit an inquiry represent different outcomes; a single universal benchmark does not capture this distinction.